1. Field of the Invention
This invention relates to the collection, densification and storage of recyclable commodities, and more particularly to a machine for densifying and storing recyclable commodities that utilizes a pneumatic device for creating suction to convey densified commodity into storage. Even more particularly, it relates to a filter system for preventing densified commodity from entering the pneumatic device and releasing to the atmosphere, the filter system having filter cleaning capabilities.
2. Description of the Prior Art
With the increasing emphasis in recent years on environmental protection, the recycling of used beverage containers and other similar commodities has become an important factor in the conservation effort. More specifically, the recycling of aluminum, glass and plastic containers has proven to be environmentally beneficial.
On the other hand, non-returnable containers for beverages and other goods are widely used because their cost has been less than the cost of recycling and/or cleaning reusable deposit containers and bottles. One significant effect of the widespread use of non-deposit containers has been increased litter in public places, and overflow of garbage dumps and landfills.
To combat litter and increase the amount of material that is recycled, several states have enacted mandatory "deposit laws" which require the use of containers having an added deposit cost. When the customer purchases a product in such a container, a container deposit, typically one to five cents, is added to the purchase price. After consumption of the product, the consumer can obtain a refund of the deposit by returning the empty container, often to the retailer, for recycling. The amount of the deposit may be adjusted to create an incentive for returning the container that is greater than the inconvenience in doing so. In these states, retailers generally collect the used containers and sell them to distributors or others who pay the retailer for the scrap value of the containers plus an amount to cover the retailer's handling costs.
Since the high labor cost of processing recycled material often makes recycling uneconomic, especially for retailers, various automatic machines that accept material for recycling and issue deposit refunds have been proposed. These machines relieve the burdens on the grocery industry and those who must collect the containers, pay the refunds, and store the returned commodities. For example, Applicants' assignee is the owner of U.S. Pat. Nos. 4,324,325, 4,345,679, 4,440,284, 4,469,212, 4,492,295, 4,573,641, 4,579,216, 4,784,251, and 5,226,519. All of these patents relate to machines and systems for automated redemption of beverage containers.
Another approach to improving the economics of recycling is to increase the scrap value of the recycled material. One method for increasing the scrap value is to segregate the returned material into groups whose scrap price is inherently higher than the scrap price of unsegregated material. Separation of scrap by composition (for example, glass and plastic) or by color (for example, clear glass and green glass) greatly increases the value of the scrap material. Separation of plastic scrap further according to chemical make-up is also desirable with vinyl-based container scrap being excluded from mixture with high density polyethylene, polypropylene, and polyethylene terephthaleate (PET) container scrap.
In the past, segregation of returned containers has been labor intensive, so that the labor to perform the sorting can sometimes cost more than the increase in resale value of the segregated material.
The device disclosed in U.S. Pat. No. 5,226,519 discloses a device for receiving various different types of commodities and maintaining separation of each type. However, this device includes a plurality of collection stations for receiving a plurality of commodities through a plurality of insert ports, each port for receiving one different predetermined type of commodity. The device requires the consumer to first insert all containers of one type (for example, cans) into one collection station, and receive a payment for those containers. Next, the consumer inserts containers of another type in another collection station for a separate payment. A consumer having three types of containers to recycle must therefore stand in three separate lines at three separate collection stations and receive three separate payments. Further, the multiple stations require the retailer to provide a large amount of space to house the devices.
Prior recycling machines have used a variety of distribution systems to move the shredded, crushed, or densified containers to storage. Gravity, feeding paddles, forced air blowers, vacuum systems, and conveyor systems, have been used with varying degrees of success. Recycling machines that have used vacuum systems have been extremely effective at moving the densified materials into storage.
The vacuum system has a filter to prevent particles of densified containers from going into the vacuum device itself and the atmosphere. The hostile environment of densified aluminum, PET, and especially glass creates problems with filter clogging. Glass is particularly harsh on the filter due to dust sized particles of glass becoming imbedded in the filter. A clogged filter in the vacuum system will cause insufficient airflow for moving the densified commodity to storage and cause the filter media damage, thereby causing the machine to fail. This situation is especially undesirable in jurisdictions where retailers are obligated to accept returned containers. An inoperable machine may result in disruption of the retailer's operation, causing him to sort and store the containers manually until the machine is repaired.
Attempts to address these difficulties have centered on providing the vacuum system with a shaker or vibration device to knock off the clinging and caked particles. However, shaking or vibrating the filter only removes particles caked onto the surface of the filter in bulk.
It is desirable to provide the capability of thoroughly cleaning the filter in the vacuum system of a recycling machine to maintain a reliable and efficient operating unit.